What are the effects of high moisture content in hot melt adhesive particles? This is how to solve problems such as bubbles, white spots, and weak adhesion

Direct answer:Hot melt adhesive granulesAfter absorbing water, the machine may experience bubbling of the melt adhesive, white spots on the adhesive layer, and decreased adhesion. In severe cases, the entire pot of adhesive may be scrapped

Hot melt adhesive particles are hydrophobic but porous particles that will slowly absorb moisture after prolonged exposure after opening. The glue particles that have absorbed water are heated in the glue pot, and the water evaporates instantly into bubbles mixed in the glue, leaving pinholes and white spots after cooling; Water vapor also weakens the wetting of paper fibers by the adhesive, resulting in weak adhesion and falling pages.

What types of problems can high moisture bring

How to determine if the rubber particles are damp

• A new bag is poured into the glue groove, and there is obvious bubbling and a “sizzling” sound on the surface, indicating that it is basically damp.
• The finished book back or adhesive layer has fine white spots and matte surface, rather than uniform transparency.
• Under the same setting, if the adhesion suddenly deteriorates, priority should be given to suspecting moisture rather than equipment.

solution

• preventionTighten the bag opening as needed, control humidity in the warehouse (try to keep it below 60%), and store it away from the ground; In summer, goods are first hung and then stored in the warehouse.
• Mild dampnessCan be dried at low temperature (60-80 ℃) for 1-2 hours for dehumidification before running on the machine, but do not dry at high temperature for a long time.
• Severely damp/carbonizedDirectly scrap and clean the pot, don’t settle for it, otherwise blocking the gun will be more troublesome.

FAQ

Q: Does the nominal “moisture-proof” rubber particle not absorb water?
Answer: Moisture prevention is to delay or eliminate it. Long term exposure can still absorb moisture, and storage habits are the key.

Q: Will the performance of damp rubber particles recover after drying?
Answer: Mild moisture and drying can restore most of the performance; If it has clumped or turned yellow, the ingredients may have changed and it is not recommended to use it again.

Q: How can I ensure that the glue I bought is dry?
Answer: Choose products with sealed packaging and fast delivery. Guangzhou Sunlife TradingSunlife Hot Melt AdhesiveUsing moisture-proof inner lining bags, it is also recommended to store the goods in their original bags during the southern rainy season, use them as needed, and attach storage instructions to reduce the risk of moisture.

One sentence: High moisture content in rubber particles=bubbles, white spots, and weak adhesion. To prevent this, it is necessary to store it in a sealed environment and control the humidity. If it gets damp, it should be lightly dried and heavily scrapped.